There are various designs of bicycles and scooters (hereinafter referred to simply as a bicycle) which may be folded for storage or carrying purposes. Some of these have a conventional bicycle frame of a diamond configuration and standard diameter wheels carried on arms hinged to the main frame, or removable wheels to permit folding of the frame. However, the shape and dimensions of these when folded often are most inconvenient for carrying. There have also been proposals where the main frame is designed to hinge to a collapsed position, with protruding parts hinging or telescoping with respect to the main frame, but these tend to be difficult to open out for use, or to collapse for carrying. Moreover, many designs are somewhat unstable when unfolded and so unsettling to ride. In an attempt to make a folding bicycle more easy to carry when folded, it is also known to provide a separate rigid case or flexible bag in which the collapsed bicycle is placed, but there then results the problem of transporting the case or bag, when the bicycle is in use.
In GB-2119324-A (Selars) there is described a bicycle having no main frame as such, but which has a part of a case serving as a main load bearing structure and into which may be folded a handlebar assembly and a seat assembly. The rear wheel is provided on an arm which may pivot round to lie partly within the case, the case being completed by a second part which when unfolded overlies the rear wheel. A disadvantage of this arrangement is that the main chain wheel (driven by the pedals) must be of a relatively small diameter to fit within the case and not protrude when the bicycle has been folded. To overcome this problem and obtain suitable gearing, a second large diameter chain drive wheel is provided on the pivoting arm section, so greatly adding to the mechanical complexity and weight of the structure, as a whole.
WO-85/01711-A (Miller) shows a bicycle with a case having a section hinged to the main part of the ease, to reduce the side area of the case and so to expose the rear wheel. The front wheel is arranged to be folded out and then locked in a position adjacent the lower front edge of the case. The disadvantage of this arrangement is that the length of the case will determine the distance between the front and rear wheels when the bicycle is unfolded as the location of the rear wheel axle is fixed within the case and the front wheel axle cannot lie significantly beyond the vertical front edge of the case. Since a bicycle must have a certain minimum dimension between the front and rear wheel axles for safety in use, a relatively long and consequently heavy case is required.
WO-83/03232 (Licencia Talalmanyokat) shows a bicycle which may be folded down to form a case-like structure, the case being defined by structural parts which are pivoted together and form the frame, when opened out. Such an assembly, having many pivoted parts, does not provide a rigid structure defining the required geometery for a bicycle and of necessity it has a very low gearing.